This application is based on Japanese Patent Application No. 2002-289794 filed on Oct. 2, 2002, the disclosure of which is incorporated herein by reference.
The present invention relates to a resinous heat exchanger constructed of a plurality of plate members defining inside fluid passages therein and a method of manufacturing the same. The heat exchanger is for example suitable in use as an evaporator for a vehicle air conditioner.
JP-A-2001-41678 (U.S. Pat. No. 6,401,804 B1) discloses a heat exchanger constructed of a plurality of flat tubes without interposing fins between them. Each of the flat tubes is formed by joining a pair of aluminum plates such that inside fluid passages are formed therein. The flat tubes are layered such that outside fluid passages are formed between the adjacent tubes. Thus, the heat exchanger performs heat exchange between an inside fluid, such as refrigerant, flowing inside the flat tubes and an outside fluid, such as air, passing through the outside fluid passages. Since the heat exchanger is constructed of the layered aluminum plates, it is generally heavy in weight.
JP-B2-2749586 (U.S. Pat. No. 4,955,435)discloses a panel heat exchanger without having fins. A panel is formed by opposing two resinous sheets and bonding the two resinous sheets at necessary positions, so that header portions and fluid passages are formed in the panel. Since the heat exchanger is made of the resin material, it is generally light in weight. However, the panel requires a large heat exchanging surface area for maintaining efficiency of heat exchange. Therefore, it is likely to be difficult to maintain spaces for outside fluid passages when in use.
The present invention is made in view of the foregoing matter and it is an object of the present invention to provide a heat exchanger, which is made of resin and capable of improving productivity.
It is another abject of the present invention to provide a method of manufacturing a resinous heat exchanger, which is simple and capable of improving productivity.
According to the present invention, a heat exchanger includes a core portion made of resin and tank portions connected to ends of the core portions. The core portion includes a plurality of heat exchanging plate portions each forming inside fluid passages therein and a holding portion. The heat exchanging plate portions are layered with predetermined spaces between them and held by the holding portion. The heat exchanging plate portions and the holding portion are integrally formed into a single piece.
Accordingly, since the core portion is made of resin, it is light in weight. Also, it improves productivity. Preferably, the core portion is formed by removing predetermined portions from a resinous extrusion body. Accordingly, the core portion is easily produced, thereby improving the productivity of the heat exchanger.